Merge pull request #700 from netbox-community/renovate/ruamel.yaml-0.x

Update dependency ruamel.yaml to v0.17.21

Author: cimnine

requirements-container.txt

@@ -1,5 +1,5 @@
 napalm==3.3.1
-ruamel.yaml==0.17.20
+ruamel.yaml==0.17.21
 django-auth-ldap==4.0.0
 google-crc32c==1.3.0
 django-storages[azure,boto3,dropbox,google,libcloud,sftp]==1.12.3